Re: [PATCH RFC bpf-next 0/3] libbpf: add better syscall kprobing support

[Alan Maguire <alan.maguire@oracle.com>]

On 12/07/2022 05:24, Andrii Nakryiko wrote:

> Sounds good! I'll add that to bpf_program__attach_ksyscall() doc
> comment (and to commit message). I'll implement those new virtual
> __kconfig variables that I mentioned in another thread and post it as
> v1, hopefully some time this week.
> 

This is really useful, thanks for doing it! I tested on arm64,
only issue was the tracefs path issue that I think was already
mentioned, i.e. for me it took

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 4749fb84e33d..a27f21619cfc 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -4685,7 +4685,7 @@ static int probe_kern_syscall_wrapper(void)
         * kernel was built with CONFIG_ARCH_HAS_SYSCALL_WRAPPER and uses
         * syscall wrappers
         */
-       static const char *kprobes_file = "/sys/kernel/tracing/available_filter_functions";
+       static const char *kprobes_file = "/sys/kernel/debug/tracing/available_filter_functions";
        char func_name[128], syscall_name[128];
        const char *ksys_pfx;
        FILE *f;

...to get the feature probing - and hence auto-attach to the
right arch-specific probes - to work.

Alan